as in treacherous
formal
causing harm in a way that is gradual or not easily noticed
Most people with this insidious disease have no idea that they are infected. an insidious enemy
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Example Sentences
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Recent Examples of insidious
Amid the coming-out balls, proposals and a whopper of a divorce scandal, a more insidious theme emerged: the rise of fascism in Europe, and two of the sisters’ infatuation with it.
—
Kimberly Roots, TVLine, 24 June 2025
Sports nostalgia is one of the more insidious forms of the whole misty-watercolor-memories racket, as that first flush of fandom tends to coincide with a time when most of us lack so much as a nodding acquaintance with critical thinking.
—Anthony Crupi, Sportico.com, 11 July 2025
Recently premiering at Tribeca, the documentary explores the war in Afghanistan and the insidious deception that the American public underwent.
—Rolling Stone, 10 July 2025
Treating it as such is an insidious form of idolatry.
—Walt Shelton, Austin American Statesman, 2 July 2025
See All Example Sentences for insidious
Kimberly Roots, TVLine, 24 June 2025
Sports nostalgia is one of the more insidious forms of the whole misty-watercolor-memories racket, as that first flush of fandom tends to coincide with a time when most of us lack so much as a nodding acquaintance with critical thinking.
—Anthony Crupi, Sportico.com, 11 July 2025
Recently premiering at Tribeca, the documentary explores the war in Afghanistan and the insidious deception that the American public underwent.
—Rolling Stone, 10 July 2025
Treating it as such is an insidious form of idolatry.
—Walt Shelton, Austin American Statesman, 2 July 2025
See All Example Sentences for insidious
Recent Examples of Synonyms for insidious
Adjective
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In addition to some light-hearted banter between Thia and Dek, the trailer also gives viewers a look at the treacherous journey ahead of them.—
Caroline Blair,
People.com,
23 July 2025
-
Airplanes can be treacherous for people who use wheelchairs.—
Joseph Shapiro,
NPR,
17 July 2025
Adjective
-
Climate change continues to have a profound impact on the Great Lakes region, bringing more extreme weather, declining fish populations, and subtle but profound economic transformation.—
Caitlin Looby,
jsonline.com,
24 July 2025
-
Interplay of rough and polished diamonds continued, with a wide range of hues from white to subtle greens and browns, and the use of materials such as natural jet and grand-feu enamel.—
Lily Templeton,
Footwear News,
24 July 2025
Adjective
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One of the things your piece says is that, essentially for the entire duration of the war, there’ve been false warnings about a hunger crisis.—
Isaac Chotiner,
New Yorker,
30 July 2025
-
Hanner said the investigative report was misleading and partially false, adding that Griffith’s actions were a direct result of advice from her supervisors and district legal counsel.—
Keri Heath,
Austin American Statesman,
30 July 2025
Adjective
-
Falter, 28, is a deceptive lefty under team control through 2028 who is enjoying his best season, with a 3.73 ERA and a 1.18 WHIP in 22 starts.—
The Athletic MLB Staff,
New York Times,
1 Aug. 2025
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The attackers use deceptive ads that imitate popular cryptocurrency brands like Binance, TradingView, ByBit and MetaMask.—
Kurt Knutsson,
FOXNews.com,
1 Aug. 2025
Adjective
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Those voting for it are Sean Elo-Rivera, Jennifer Campbell, Kent Lee, Stephen Whitburn, Vivian Moreno and La Jolla’s own Joe LaCava, who has been an active supporter of this perfidious plan.—
Inga,
San Diego Union-Tribune,
16 June 2025
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Jake Gyllenhaal is his foil as the perfidious Iago, who goads Othello into unreasoning jealousy with lies about his beloved Desdemona (Molly Osborne).—
New York Times,
New York Times,
17 Feb. 2025
Adjective
-
Beyond access control, a problem that exists for enterprise AI—just like mainstream AI chatbots—is the potential for hallucinations or incorrect responses.—
Megan Poinski,
Forbes.com,
31 July 2025
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My feeling is this question is based on a few incorrect assumptions.—
Jesse David Fox,
Vulture,
30 July 2025
Adjective
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If the calculation is wrong, everything downstream—equipment selection, duct sizing, airflow balancing—will also be off.—
Brynn Cooksey,
Forbes.com,
30 July 2025
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Anxiety about your bowel habits may stem from the belief that there’s something wrong with them.—
Sarah Garone,
Health,
30 July 2025
Cite this Entry
“Insidious.” Merriam-Webster.com Thesaurus, Merriam-Webster, https://www.merriam-webster.com/thesaurus/insidious. Accessed 6 Aug. 2025.
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